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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7812ee6695af3fd0a2487210283f76d1a96a5f4045198c428deb3ec79923dbf7' 
  AND token = 'o/UilyorX9P0Y/3Gg1e7LEfoGArT0WKgtEQ5fRAXtlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

Explain
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE								Impossible WHERE noticed after reading const tables